1. Field of the Invention
The present invention relates to the construction of an ink accommodating pouch for supplying ink to the print head of an inkjet recording device, such as a piezoelectric type inkjet recording device.
2. Related Art
There have been provided inkjet recording devices that eject ink droplets based on input signals for forming images on such recording mediums as papers.
Japanese published examined patent applications (Kokoku) Nos. HEI-3-34461, HEI-4-5549, and HEI-4-21590, and Japanese Patent-Application Publication (Kokai) No. HEI-4-211963 disclose conventional ink housing devices for use in inkjet recording devices.
FIG. 1 shows an ink housing device disclosed in Japanese published examined patent application (Kokoku) No. HEI-4-5549. As shown in FIG. 1, the ink housing device 100 has a box-shaped cartridge casing 131 accommodating an ink accommodating pouch 120 made of synthetic resin.
A rubber stopper 112 having a small-diameter portion 112a at one side, an outer portion 112c at opposite side, and a large-diameter portion 112b in the middle is fixed inside a through hole formed in the casing 131A. A cavity 114 is formed in the small-diameter portion 112a and the large-diameter portion 112b to have an opening at the one side. One end of a cylindrical ink outlet 110 is connected to the ink accommodating pouch 120 for leading ink out of the ink accommodating pouch 120. Another end of the ink outlet 110 is engaged inside the cavity 114, so that the rubber stopper 112 seals off the ink outlet 110.
Upper and lower parts 131A, 131B of the casing 131 are formed with grooves in edges, defining a through hole 140 in a joint portion between the upper and lower parts 131A, 131B. The large-diameter portion 112b is fit into a circular groove formed in an inner periphery of the through hole 140, whereby the rubber stopper 112 is fixed to the casing 131.
Usually, an ink accommodating pouch used in this type of ink housing device is produced in a following manner. That is, a flexible sheet material having gas barrier properties is folded in halt such that the edges are aligned. Two edges of the layers are joined by thermal fusion (heat sealed). An ink outlet is mounted in remaining one edge of the layers and heat sealed to the sheet. Then, the ink outlet is fitted into a rubber stopper for sealing the pouch.
FIG. 2 shows a cross-sectional view of a conventional ink accommodating pouch 200. Here, an ink accommodating pouch 200 includes two sheets 201a and 201b placed one over the top of the other and joined together at junctions 202 on the edges of the ink accommodating pouch 200.
The above described conventional technologies have the following problems.
The configuration of the conventional ink cartridge 100 shown in FIG. 1 requires to form grooves in the upper and lower casing 131A, 131B that define a stepped through hole, that is, the through hole 140 with the circular groove formed in the inner periphery thereof, such that the large-diameter portion 112b of the rubber stopper 112 is engaged with the stepped through hole for fixing the rubber stopper 112 to the casing 131. This configuration, however, increases the manufacturing costs of the ink cartridge 100. Further, because it is not possible to insert the rubber stopper 112 into the through hole 140 in a condition where the upper and lower casing 131A, 131B are engaged with each other, mounting process of the rubber stopper 112 onto the casing 131 is not easy.
Also, a surface area of the ink outlet 110 that contacts the rubber stopper 112 is relatively small, so that sealability for preventing ink leakage through a sealing surface between the ink outlet 110 and the rubber stopper 112 is insufficient, causing undesirable leakage of ink.
Because the ink outlet has a three-dimensional shape with its circular cross-section or the like, a process for sealing a joint portion between the periphery of the ink outlet sealed to the sheet and the joined edges of the sheet is difficult, so that ink easily leaks through the joint portion.
Further, in FIG. 2, even when the two sheets 201a and 201b separate from each other as ink is introduced into the ink accommodating pouch 200, the angles 41 formed between the sheets 201a and 201b from the edges toward the center as are acute angles having a small interval near the junctions 202. Furthermore, the junction 202 on each side protrudes outside an accommodating portion of the ink accommodating pouch 200. This configuration produces a small ratio of cross-sectional surface area of the ink accommodating pouch 200 to a surface area (a project area of widthwise surface) of the sheet 201a, 201b. Therefore, in order to accommodate the ink accommodating pouch 200 filled with ink inside a flat, square ink cartridge, such as the casing 100 shown in FIG. 1, dimensions of the ink cartridge must be large. For this reason, dimensions of the inkjet recording device also are increased, preventing a compact design.
In view of forgoing, it is an object of the present invention to overcome the above problems, and also to provide an ink housing device that reliably prevents leakage of ink and that allows a user to easily mount an ink accommodating pouch.
It is another object of the present invention to provide an ink accommodating pouch capable of reliably preventing ink leakage.
It is also an object of the present invention to provide an ink accommodating pouch for an inkjet recording device having an increased projected area of the widthwise surface on the pouch.
In order to overcome and other object, according to the present invention, there is provided an ink accommodating device including a casing, an ink accommodating pouch, an ink outlet, and a sealing member. The casing has sidewalls. One of the sidewalls is formed with a mounting hole. The ink accommodating pouch is accommodated in the casing. The ink outlet is provided to the ink accommodating pouch and formed with a through hole. The sealing member is formed of a resilient material and seals off the through hole of the ink outlet. The sealing member is engaged inside the mounting hole by force fitting the sealing member into the mounting hole.
There is also provided an ink accommodating pouch including a pouch and an ink outlet provided to the pouch. The pouch is formed of a single sheet folded in half whose edges are sealed to form a junction, and the ink outlet is attached to a surface of the single sheet at a position other than the junction.
Further, there is provided an ink accommodating pouch including a pouch and an ink outlet provided to the pouch. The pouch has an upper sheet portion and a lower sheet portion both formed of a synthetic resin. The upper sheet portion has an edge, and the lower sheet portion has an edge attached to the edge of the upper sheet portion to form a junction The junction protrudes inward of the pouch.